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Oil Boiler HW causing rads to get Hot

Discussion in 'Plumbing and Central Heating' started by Extooth, 25 Sep 2017.

  1. Extooth

    Extooth

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    Hey,

    I Have an old Worcester Bosch Oil Boiler - Heat slave I believe.. I've recently connected a WiFi thermostat to it. Its all working as it should. But something happens that i'm not sure is normal, if perhaps someone knows something about it. When the Hot water is on, for around 2 - 3 hours.. (we left it on by accident that's how i found out), the rads get quite hot as if the heating is also on. I'm unsure if this problem has always been like this as i recently moved it, or if i wired something incorrectly.. Like i said, everything seems to be in working order apart from that..

    Any ideas?

    Many Thanks!
     
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  3. Burnerman

    Burnerman

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    Above the water pump ( boiler front cover off) there is a diverter valve, that either feeds heated water to either the internal Heatslave hot water tank or the radiators. If this isn't functioning correctly, hot water will flow to where you don't want it. Thankfully it's just the power head top that you need to examine, and it's fairly simple to attend to.
    John :)
     
  4. Terrywookfit

    Terrywookfit

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    Unless it's the Honeywell diverter with the grey plastic head......And the cartridge is fooked !!
     
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  5. Extooth

    Extooth

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    So its definitely not normal... Is this something i should get the boiler guy in for?
     
  6. Burnerman

    Burnerman

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    If the valve has the aluminium box on the top ( that's the power head) it is renewable......basically it's a small motor that opens and closes the valve. The valve sweeps only a few degrees, and a ball blocks off the valve outlet. It's a 3 port valve......hot water enters from below and then either diverts to left or right.
    The power head motor is replaceable on it's own, and it drives a brass quadrant via a small gear wheel.
    John :)
     
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  8. oilhead

    oilhead

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    If the valve is passing and it is one of the metal headed ones, then the problem is unlikely to be just in the head. If the grey plastic head, then as Terry says the cartridge will need changing. Call in the professional.
     
  9. oilboffin

    oilboffin

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    If it's the cartridge type try gripping the small pin with pliers and moving it up and down a few times it may sort it for a while if not you've a cartridge to change sometimes easy sometimes very hard good luck.Bob
     
  10. stem

    stem

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    Seems coincidental, that the fault has occurred at the same time that the room thermostat was changed. You could try disconnecting one of the switching wires from the thermostat. If the heating still comes on then, you will know it's not a wiring fault.
     
  11. Terrywookfit

    Terrywookfit

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    A demand for water overrides any heating demand and closes the valve. !!
     
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  12. oilboffin

    oilboffin

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    Yup it does.Bob
     
  13. DIYnot Local

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